WARNING: Graphic clinical images are within this blog

I regularly use a class 3b LASER (Light Amplification by Stimulated Emission of Radiation) during my treatment of dogs for neuromusculoskeletal conditions. I chose a class 3b because it is transportable and time efficient.

What is LASER?

The class 3b laser produced by Chattanooga produces electromagnetic radiation with a power of 500mW and a wavelength of 830nm. This means that it can penetrate both skin and deeper tissues and be absorbed by the cell membranes without being damaging to the eye unless directly pointed at in (Passarella and Karu 2014; Chung et al. 2012; University of Kentucky 2022). A class 3b laser is non-heating and only used for therapy whereas a class 4 laser may be either a non-heating or heating, and therefore used during surgery as a cauterizer.

How does it affect pain and tissue healing?

Chromophores in the cells absorb the light energy. This sets of a number of biological effects including oxygen production, changes in calcium ion balance and cell membrane permeability, and ATP production thereby promoting cellular health. Another effect is a reduction in inflammation by reducing production of cytokines as well as promoting tissue repair by facilitating collagen synthesis, growth factor release and fibroblast development. Laser may also increase capillary production within injured tissues. By either increasing the metabolism of endogenous opiates or, nerve conduction latency laser may assist in reducing pain. It is important to note that the effects of laser are dependent on the parameters selected and many studies have failed to select appropriate parameters within their design (Niebaum et al. 2022).

Evidence in osteoarthritis (OA)

Osteoarthritis (OA) is the most common cause of chronic pain in dogs. It affects 80% of dogs over the age of 8 years old, and potentially up to 35% of dogs of all ages (CAM, 2022). One of the mechanisms that laser aids OA may be by increasing the thickness of the cartilage (S et al. 2016). Numerous canine OA specific studies have shown that Laser is not only more effective in decreasing lameness and pain but may also lead to a reduction in use of NSAIDS. Laser may not only be offered as an alternative to NSAIDS but it may also increase client patient satisfaction (Looney et al. 2018; Barale et al. 2020; Rottman 2021). Although study numbers are small and non-standardised these findings collaborate those found in humans. Based on this one health model, the forementioned benefits of laser may be further enhanced by the addition of strengthening exercises (Alfredo et al. 2022; CDC 2022; Stausholm et al. 2022).

Evidence in wound healing

There are only 5 studies that have researched the effect of laser on wound healing in dogs. All have varying methodologies and the results are mixed but generally positive. The disparity may be due to the lack of agreement in laser parameters used (De Braekt et al. 1991; Gammel et al. 2018; Kurach et al. 2015; Lucroy et al. 1999; Wardlaw et al. 2019). Nevertheless, laser may facilitate collagen synthesis and create a greater collagen content within treated wounds (Tatmatsu-Rocha et al. 2016; Guerra Fda et al 2013; Ranjbar and Takhtfooladi et al. 2016). In a 2004 Meta analysis of the available literature of laser for wound healing by Woodruff et al. (2004), the laser treatment modality was found to be highly significant (d=+2.22). Further sub-analyses revealed that the efficacy for animals was +1.97 and for humans +0.54. Twenty-four studies met the inclusion and exclusion criteria. In another Meta analysis on tissue repair [Enwemeka et al. 2004], the outcome was +1.81. The number of studies was thirty-four. Personally, I have seen evidence of the effectiveness. The below pictures are of a 2yr old Springador whom degloved his hindlimb on barbwire. Following surgery and antibiotics followed by 4 weeks of laser therapy, isometric strengthening exercises and graduated lead walking you can see the difference and he had 0/10 lameness.

Permission gained from owner to share

Evidence in tendinopathies

Despite the ability of tendons to adapt to loading, repetitive use often results in injuries, such as tendinopathy, which is characterized by pain during activity, localized tenderness upon palpation, swelling and impaired performance (Magnussen et al. 2010). Marques et al. (2016) found that laser promotes healing of tendinopathy as they found that it produced increased collagen production. A recent systematic review by Junior and Junior (2015) found that laser demonstrates consistent effectiveness in treating tendinopathy. The American Physical Therapy Association (APTA) Clinical Guidelines recognises the weight of the evidence for treating achilles tendinopathies effectively in that they recommend laser. Including laser as part of a rehabilitation programme has also been shown to be effective for both biceps brachii and supraspinatus tendinopathies in a canine case study and in my own experience (Racoub 2019).

Evidence in neurology

All early in vivo studies using laser have been effective in regenerating and restoring nerve sensitivity following injury (De Oliveira et al. 2014). This has transpired into canine clinical research whereby Draper et al. (2012) demonstrated how laser may promote functional recovery of nerves whereby dogs undergoing a hemilaminectomy for IVDD had a more rapid return to ambulation with laser compared to no laser. Personally, I have treated two dogs and a human for “sciatica” due to peripheral nerve entrapment. They all recovered within 4 weeks through a combination of medications, laser, exercises and soft tissue therapy.

References:

Alfredo et al. (2022). https://journals.sagepub.com/doi/abs/10.1177/02692155221111922

Barale et al. (2020). https://www.ajol.info/index.php/ovj/article/view/194984

CAM (2022). https://caninearthritis.co.uk/what-is-arthritis/arthritis-the-basics/

CDC (2022). https://www.cdc.gov/onehealth/index.html

De Oliveira et al. 2014. Benefits of laser phototherapy on nerve repair | SpringerLink

Enwemeka C S, Parker J C, Dowdy D S et al. The efficacy of low-power laser in tissue repair and pain control. A meta-analysis study. Photomed Laser Surg. 2004; 22 (4): 323-329

Looney et al. (2018). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6091142/

Niebaum et al. (2022). Canine Sports Medicine and Rehabilitation (2nd edition). Chapter 7. Rehabilitation Physical Modalities.

de Braekt, M. M. H. I., van Alphen, F. A. M., Kuijpers-Jagtman, A. M. & Maltha, J. C. 1991. Effect of low level laser therapy on wound healing after palatal surgery in Beagle dogs. Lasers in Surgery and Medicine, 11: 5, 462–470. DOI: https://doi.org/10.1002/lsm.1900110512

Gammel, J. E., Biskup, J. J., Drum, M. G., Newkirk, K. & Lux, C. N. 2018. Effects of low-level laser therapy on the healing of surgically closed incisions and surgically created open wounds in dogs. Veterinary Surgery, 47: 4, 499–506. DOI: https://doi.org/10.1111/vsu.12795

Kurach, L. M., Stanley, B. J., Gazzola, K. M., Fritz, M. C., Steficek, B. A., Hauptman, J. G. & Seymour, K. J. 2015. The Effect of Low-Level Laser Therapy on the Healing of Open Wounds in Dogs. Veterinary Surgery, 44: 8, 988–996. DOI: https://doi.org/10.1111/vsu.12407

Lucroy, M. D., Edwards, B. F. & Madewell, B. R. 1999. Low-Intensity Laser Light-Induced Closure of a Chronic Wound in a Dog. Veterinary Surgery, 28: 4, 292–295. DOI: https://doi.org/10.1053/jvet.1999.0292

Magnussen et al. 2010. The pathogenesis of tendinopathy: balancing the response to loading - PubMed (nih.gov)

Wardlaw, J. L., Gazzola, K. M., Wagoner, A., Brinkman, E., Burt, J., Butler, R., Gunter, J. M. & Senter, L. H. 2019. Laser Therapy for Incision Healing in 9 Dogs. Frontiers in Veterinary Science, DOI: https://doi.org/10.3389/fvets.2018.00349

Woodruff L D, Bounkeo J M, Brannon W M, Dawes Jr K S et al. The efficacy of laser therapy in wound repair: a meta analysis of the literature. Photomed Laser Surg. 2004; 22 (3): 241-248

Tatmatsu-Rocha et al. 2016

Guerra Fda et al 2013

Ranjbar and Takhtfooladi et al. 2016